Stain



Patented Nov. 24, 1942 STAIN Edmond H. Buoy, Stamford, Conn., assignor to Atlas Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 21, 1940, Serial No. 336,358

12 Claims.

The present invention relates to improvements in stains.

More particularly, this invention relates to a stain of the water type, although as will hereinafter appear, stains of the present invention may have a proportion of organic solvent in the vehicle.

Staining is one of the initial operations in the finishing of porous materials such as wood and since the pores are unfilled when the stain is applied, it is diflicult to obtain uniform application of color. This difliculty is experienced with water stains and is most pronounced with spirit stains which tend to sink into wood very rapidly. The use of oil stains results in slower penetration, thustending to provide for greater uniformity, but the reduction in penetration gives a less solid or less opaque color. Moreover, oil stains have other well known disadvantages such as their incompatibility with many types of overcoats,

and the tendency of the oil soluble stain to bleed into whatever overcoat is applied. In addition,

oil soluble colors are generally fugitive and the igniting finish is likely to fade badly in a short While water stains seem to be superior to oil and spirit stains insofar as the application of uniform solid color is concerned, water stains are by no means perfect in this respect and, in addition, have the property of raising the grain of the wood, thereby causing annoyance and additional labor to the finisher. come these diiliculties it has been proposed that the surface be treated prior to-staining. Thus,

where rapid penetration of the stain is to be overcome, it has been proposed that the surface first be sized with a coat of glue or the like. Where the raising of the grain is objectionable, the'bare wood. may be first wetted to raise the grain, and this, when dried, is sandpapered off. These pretreatment steps are costly and generally unatisfactory since they must be varied,

with different porous materials.

From time to time it has been proposed that stains of the water type might be improved by the addition of water soluble or water dispersible materials such as molasses, starch, and water solution of shellac. Some of these addition agents have had a measure of usefulness but usually the bad effects were more noticeable. The materials that are organic in nature are subject to decomposition through fermentation, molding, etc. Shellac was found to be incompatible with certain overcoats and was subject to dissolution by some of the solvents employed In order to overtherein. As a result water soluble or water dispersible addition agents are not generallyemployed in stains of the water type at the present time.-

An object of the present invention is to provide an improved stain of the water type.

Another object of the invention is to provide an improved water stain comprising a watersoluble resinous binder.

A further object of the invention is to provide a stain of the water type which gives a uniform application of solid color, eliminates the necessity for pretreatment of the surface to be stained, dries rapidly, and which provides for the ready application of fillers and overcoats.

' Greatly improved stains of the water type can be prepared by the addition of a boric acid resin of a polyhydric alcohol which resin is watersoluble and retains its resinous properties upon drying out of water solution. Examples of such resins are the boric acid resins of the hexitols,

" glycerol or ethyleneglycol, among which the neutral resins of sorbitol and mannitol are preferred.

The hexitol borates for use in the present invention can be prepared as described in the applications of Clarence Bremer, Ser. Nos. 149,839, filed June 23, 1937; 196,387 and 196,414 both filed March 1'7, 1938; and 200,127 filed April 5, 1938. Unneutralized boric acid-hexitol resins are strongly acidic and for some applications this acidity may be objectionable. Moreover, the

neutralized resins are more resistant to hydrolysis than the acidic resins. I, therefore, prefer to neutralize the resin by the addition of an alkali hydroxide, preferably sodium or potassium hydroxide.

Instead of using a Pure hexitol for preparing the resin a more economical commercial mixture can be employed. For example, in the case of sorbitol there is available a commercial syrup produced by the electrolytic reduction of glucose and which contains a major portion of sorbitol and also considerable quantities of non-hexitol polyhydroxy bodies. This material has been found to make resins with boric acid which are eminently suitable for the purpose of the present invention.

Qhe coloring material used in the stain of the present invention may be any of the wellknown water soluble or water dispersible powders such as the various vegetable and mineral stains and water soluble aniline dyes. As examples may be cited sienna, umber, tumeric, g'amboge, dragonsblood, wool orange, Nigrosine, wool yellow, etc.

I have found that the presence of small proportions of the water soluble borate resins in stains of the water type results in markedly superior products. Stains having the resin present in amounts as low as 2 by weight give excellent results. Preferably the resin is present in a proportion of from 5-10% by weight and the proportion of resin should not exceed by weight (total solids should not exceed by less coloring matter is required when the borate 20 resin is employed. When stains of the present invention are employed the surface need not be previously treated, the necessity for shellac or other wash coats being eliminated. Even though the resin itself is of a rubbery nature, the stain surface may be free-sanded without showing uneven spots or areas on the sanded surface.

After application of a stain ofthe present invention, fillers wipe in better and cleaner con; trast of color is obtained. Subsequent coats of finish are held as tightly as though an actual sealer coat had been used and the durability of the ultimate finish is enhanced. Moreover, the ultimate finish has a greater brilliance of color.

The stain of the present invention may advantageously contain surface active or wetting agents such as sulpfionated olive oil, sulphonated castor oil and the like. Inert pigments such as aluminum stearate, zinc stearate, magnesium carbonate and sodium silicate may be included to promote ease of sanding. -Where the coloring matter or dyestuff employed is difficultly soluble in water, water-soluble organic solvents may be utilized, as for example diethyleneglycol, butyl cellosolve, dioxane, and ethylene-glycol monomethyl ether. Where such organic solvents are employed they are only assistant solvents and are used in relatively small percentages, say, not over 10 or 15%, Just enough to give the necessary solvent power to the stain.

While the invention is capable of great variation as to proportions, the selection of coloring materials, surface active agents and the like, the following examples will serve to illustrate the invention to those skilled in the art.

Example 1 A neutral sorbitol-boric acid resin useful in the present invention can be made as follows:

182 g. (1 mol) sorbitol and 62 g. (l-mol) boric acid dissolvedin 180 g. of water were heated at 110-115 C. until the water of solution and 2 mols of water of condensation had been volatilized. The melt was then cooled to a temperature below 100 C. and a aqueous solution of NaOH added until a pH of 7.0 was obtained. This neutralization required exactly 0.8 mol NaOH. Thereupon the neutralized mix was heated above 100 C. for suilicient time to evaporate the water introduced in the neutralization.

The product was an extremely viscous water soluble resin which had excellent binding power and which retained its resinous character upon drying out of water solutien.

In the preceding example mannitoi or any of the other hexitols can be substituted for sorbitol. In place of pure sorbitol, a commercial product containing a substantial quantity of sorbitol together with other polyhydroxy bodies can be used.

Example 2 A stain of the present invention is illustrated by the following composition, parts being by weight:

Parts Sodium sorbitol borate (product of Example 1) 10 Walnut crystals 2 W001 orange A .125 Nigrosine black .125 Water 134 In preparing stain of the above composition the sorbitol borate may be dissolved in the water and the.coloring materials dispersed in the sorbitol borate solution. Alternatively the coloring materials maybe dispersed in a small proportion of sorbitol borate solution and thereafter mixed with the additional sorbitol borate and water required to make up the composition.

Example 3 A stain of the present invention may be prepared in accordance with the following wherein "parts means parts by weight:

Sodium sorbitol borate of Example 1 is dissolved in water in the proportion of three parts of resin and 9 parts of water, this solution being referredto in this example as solution A.

16 parts of solution A are thoroughly dispersed in a pebble mill with 11 parts of sulphonated olive oil and 16 parts of aluminum stearate. The dispersion so produced is removed from" the mill and mixed'with 66 parts of ethyleneglycol monoethyl ether and 2265 parts of solution A to form a clear'base which may be stored in relatively large quantities. Portions of the clear base (hereinafter referred to as solution B) may be withdrawn and mixed with the desired coloring material as required. A stain employing solution B is as follows:

This stain gave excellent results when sprayed full weight on wood and air dried for from one to two hours.

Example 4 A glyceryl borate resin can be prepared as follows:

Heat 184 g. (2 mols) glycerol and 124 g. (2 mols) boric acid slowly, holding it at approxiinately 10 degree intervals until rapid boiling ceases at each temperature. Samples taken at different temperatures were very soft on cooling until the reacting mass reached 135 C. when the samples began to show signs of resin formation by thickening on cooling. At 145 C. the mass is becoming resinous. 0001 to C. and neutralize by the addition of 25 ml. of an aqueous NaOH solution of 500 g. per liter, concentration. Reheat to C. until rapid boiling ceases. The

product on cooling is a fairly hard glassy resin. In place of glycerol the same reaction can be performed by substituting ethylene glycol in the same molar ratio and heating until the mass becomes resinous.

tion is a glycol borate resin.

Example 5 A stain having the composition of the stain of Ex. 2 but wherein' the glycerol or ethylene glycol borate of Ex. 4 is substituted in whole or in part for the sorbitol borateof Ex. 2.

Example 6 stable in can and drum stock as they are substantially neutral. While the glycerol and glycol resins give excellent results the hexitol resins are highly preferred since stains comprising the hexitol resins dry harder and provide a superior surface for subsequent finishing coats. The use of wetting agents, inert pigments, organic solvents and other ingredients frequently utilized in the production of stains may be desirable in special cases, but I have found that the addition of such ingredients is not required in the majority of applications.

Having fully described my invention, claim is as follows:

1. A stain of the water type comprising water, coloring material and a binder consisting of a boric acid-polyhydrlc alc'ohol resin which is water soluble and which retains its resinous character on drying out of water solution.

2. A stain -'of the water type comprising water, coloring material and a binder consisting of a boric acid-polyhydric alcohol resin which is water soluble and which retains its resinous character on drying out of water solution, said resin being present in an efiective proportion not exceeding by weight. 1 w

3. A stain as set forth in claim 1 and wherein the resin is a boric acid-hexitol resin.

what I The product of such a reac- 4. A stain as set forth in claim 2 and wherein the resin is aboric acid-hexitol resin.

5. A stain of the water type comprising water, coloring material and a binder consisting of an alkali metal neutralized boric acid-hexitol resin which is water-soluble and which retains its resinous character upon drying out of water solution.

6. A stain of the water type comprising water, coloring material and a binder consisting of an alkali metal neutralized boric acid-hexitol resin which is water soluble and which retains its resinous character upon drying out of water solution, said resin being present in an efiective proportion not exceeding 25% by weight.

7. A stain of the watertype consisting essentially of water, coloring material and a binder consisting of a boric acid-polyhydric alcohol resin which is water soluble and which retains its resinous character on drying out of water solution, the solids content of said stain not exceeding 30% by weight and the said resin be ing present in an effective amount not exceeding 25% by weight.

8. A stain as set forth inclaim '7 and wherein the resin is a boric acid-hexitol resin.

9. A stain as set forth in claim 7 and wherein the resin is an alkali metal neutralized boric acid-hexitol resin.

10. A stain as set forth in claim 1 wherein the coloring material is selected from the class consisting of water soluble and water dispersable coloring materials.

11. A stain-as set forth in claim 6 wherein the coloring material is selected from the class consisting of water soluble and water dispersible coloring materials.

12. A stain of the water type comprising water, coloring material selected from the claw consisting of water soluble and water dispersible coloring materials, and a binder consisting of EDMOND H. BUCY. 

